This invention is generally directed to electroluminescent (EL) devices, and more specifically, to organic EL devices with enhanced thermal and operational stability, and thus improved device durability, and which devices contain indolocarbazoles as the charge, and especially hole transport components.
There has been substantial interest with regard to developing an energy-efficient flat-panel display based on organic EL devices, primarily because of their potential as an emissive display technology which may offer unrestricted viewing angles and high luminescence output at low operating voltages. However, despite the recent advances that have been made in EL device design and fabrication, a number of the current EL device performances does not usually effectively satisfy the requirements for practical applications. Examples of undesirable performance characteristics include short serviceable life, high operating voltages, and low EL efficiency, and the rectification of all these performance deficiencies represents one formidable challenge in EL device research and development. Accordingly, one of the features of the present invention is to provide organic EL devices which provide for long device life span and excellent EL efficiency.